i don't support for card swapping. In many of our games, people often bet on other players' horses out of their own benefit to earn $ rather than helping each other. Thus i don't see this option of card swapping being of much use then.

It might make for an awesome variant! Since the entire point of the game is to have the most money at the end, any house rules won't really effect balance or anything, since everyone is free to wheel and deal as they see fit.

Keep in mind... If I made a guess I would say I have nearly 60 plays of Long Shot with the rules as written, and though we have joked about trading cards or horses, we have never done so, and still enjoy the game quite a bit! I do have a lot of experience with the game, so adding in some trading might change the game for us in a completely different way than someone who has only one or two races under their belts. So, take my words about game balance with a grain of salt.

I will be trying the "Let's Make a Deal" variant next time I break it out though...